The Lucent Technologies Autoplex.RTM. Cellular Telecommunications System System-1000 is a complete wireless telecommunications system whose major components include the Executive Cellular Processor (ECP) Complex, a 5ESS-2000.RTM. Digital Cellular Switch (DCS), and a plurality of cell sites. Autoplex.RTM. and 5ESS-2000.RTM. are registered trademarks of Lucent Technologies.
Service Measurements (SM) is a SM tool which allows a customer the ability to monitor call traffic and performance of their system which in turn helps them make the necessary adjustments via Recent Change/Verify forms to add new equipment, adjust existing resources, adjust timer values, re-try attempts etc. to obtain maximum performance from the system.
The CCS is the traditional unit of measurement for expressing switched traffic load. A CCS unit represents one hundred (C-Roman numeral for 100) call (C) seconds (S). Traffic components (lines, trunk, calls, etc.) are scanned every 100 seconds. Each time a busy condition is found, a counter is incremented. Thirty-six 100-second scans are completed in an hour (1 Hour=3600 Seconds=36 CCS). At the end of each hour, the measuring device is recycled. If one call is busy for 30 minutes during an observation interval, a usage of 18 CCS will be measured. However, if 18 calls are busy for 100 seconds each in the observation period, 18 CCS will also be measured. Therefore, usage is a function of the number of calls and duration of time (holding time) each call is busy.
The Erlang is a well-established international unit of traffic measurement equal to the average number of busy resources or, equivalently, the average resource usage expressed in some arbitrary unit of time. Erlangs need not be referenced to any specific time interval. However, the unit of time used to express usage or call rate must always be the same unit used to express holding time and observation interval. Since traffic-engineered components are sized for a busy-hour load, a 1 hour time interval will be the base for all Erlang units used. Therefore, 1 unit of Erlang usage is equal to 36 units of CCS usage. Consider a simple example of a system that generates 3000 calls over a 1 hour observation period with an average holding time of 200 seconds per call. The traditional CCS usage would be the product of calls times holding time divided by 100: (3000 calls)(200-second holding time)/100=6000 CCS. To describe the traffic usage in units of Erlangs, the calls times holding time product would be divided by the observation interval in seconds (3600 seconds): (3000 calls) (200-second holding time)/3600=167 Erlangs.
All usage counts are stored in units of 1/100 Erlangs, unless specified otherwise (i.e., divide the usage count by 100 to get Erlangs). A usage of 1 Erlang would result if one trunk within a 3 trunk group was busy for one hour. In this case, "100" would be stored in the SM data files on disk. Similarly, if 200 trunks within a trunk group were busy for one hour, 200 Erlangs would result and "20,000" would be recorded in the SM data files on disk. The usage for a resource is determined by looking at the number of facilities (for example, trunks) in use every 10/100 second cycle, and accumulating this number.
Service measurement data are collected from the system's components, including the ECP, DCS's, cell sites, micro-cell sites, link nodes such as the Cell Site Node (CSN), Digital Switch Node (DSN), and Inter-Cellular Node (ICN), and other nodes that make up the telecommunications system, such as the Direct Link Node (DLN), the Inter-processor Message Switch/Common Network Interface (IMS/CNIO), and the Signaling System 7 (SS7). Service Measurements also allows customers to forecast or anticipate the future needs of their system so they can position themselves to offer the best quality service to the end-user. Currently, SM data are provided on an hourly basis, which does not allow the user to look for peaks, or enable the user to view the results of changes they have made on their system in a shorter interval. Customers have shown a need to view a subset of their SM counts which are related to both changes they have made in their system, and to show peaks in system resources in a shorter time frame than the current hourly interval.